The pentafluorosulfanyl group (hereinafter referred to as the SF5 group) is an electron-withdrawing and lipophilic substituent used for designing a functional organic molecule. Accordingly, a SF5 group-containing compound is crucial in the development of a liquid crystal molecule or a low molecular weight medicine/agricultural chemical molecule, and the synthetic method of such compound is recently under development (NPL1). It is particularly important to introduce a SF5 group to the pyridine ring, which is widely used as biologically active substances in pharmaceutical and agrochemicals, but the introduction of SF5 group is difficult, due to the instability of the intermediates, namely trifluorosulfanyl pyridine and halotetrafluorosulfanyl pyridine. Proposed as a method for introducing SF5 group to pyridine ring is the one using a disulfide compound as a starting material, and the disulfide is oxidized in the presence of potassium fluoride by chlorine gas and then the subjecting obtained material, through a halogen exchange reaction using silver fluoride, is converted to the compound having a SF5 group at position-2 of the pyridine ring (NPL2). However, a pragmatic method for introducing a SF5 group to position-3 or position-4 of the pyridine ring has yet to be developed. Although there is report that a SF5 group may be introduced to position-3 of the pyridine ring by fluorination of pyridyldisulfide using AgF2 (PTL1), only a single sentence is attributed to the fact, and no data of the compound such as NMR or Examples of the compound are shown. There are also other reports of bioactive compound groups that have a SF5 group introduced onto position-3 of the pyridine ring (PTL2 to PTL5), but similarly to the above, only a single sentence is attributed to the fact, and no data of the compound or Examples of the compound are shown.
There is no report of a compound having a SF5 group on position-4 of a pyridine ring, and of a compound having a chlorotetrafluorosulfanyl group (hereinafter referred to as the SF4Cl group) on position-3 or position-4 of the pyridine ring.